So what’s this fascination with tunnels? In Chicago, there are overhead elevated train tracks, and they work just fine. They seem a lot cheaper to build and maintain than tunnels. You can even build them over existing avenues. Why don’t we have more of that?
Have you ever lived near an elevated train? They're not pleasant areas, especially compared to subway stations. The area under the tracks aren't very usable, except as a roadway and parking lots. They're loud as hell, people on the trains can see into your home, the spaces around the elevated tracks are great places for people to do drugs and have crusty hobo sex. These criticisms apply equally to elevated roads. Mos…
Here (in the US) I've only ever seen 1) homeless people, 2) garbage, or 3) graffiti (and not the good looking stuff).